How many it is necessary to write to manuscripts of 750 pages figures to number all pages (to consider each figure so many time how many it is written)?

If each figure to consider so many time how many it napisanato: 9 one-digit 99-9=90 two digit 750-99=651 three digit 9*1+90*2+651*3=9+180+1953=2142 figures will leave on writing of page numbers.
Answer add